EUV light source optical elements

Abstract

Apparatus and methods are disclosed for forming plasma generated EUV light source optical elements, e.g., reflectors comprising MLM stacks employing various binary layer materials and capping layer(s) including single and binary capping layers for utilization in plasma generated EUV light source chambers, particularly where the plasma source material is reactive with one or more of the MLM materials.

Description

FIELD OF THE INVENTION [0001] The present invention relates to extreme ultraviolet (“EUV”) light generators providing EUV light from a plasma created from a source material and collected and directed to a focus for utilization outside of the EUV light source generation chamber, e.g., for semiconductor integrated circuit manufacturing photolithography process performing machines, e.g., at wavelengths of around 20 nm and below. RELATED APPLICATIONS [0002] The present application is a continuation-in-part of U.S. Pat. Application Ser. No. 10 / 979,945, entitled LPP EUV LIGHT SOURCE, filed on Nov. 1, 2004, Attorney Docket No. 2004-0088-01, and Ser. No. 10 / 900,839, entitled EUV LIGHT SOURCE, filed on Jul. 27, 2004, Attorney Docket No. 2004-0044-01, and Ser. No. 10 / 803,526, entitled HIGH REPETITION RATE LPP EUV LIGHT SOURCE, filed on Mar. 17, 2004, Attorney Docket No. 2003-0125-01 and Ser. No. 10 / 798,740, entitled COLLECTOR FOR EUV LIGHT, filed on Mar. 10, 2004, Attorney Docket No. 2003-008...

AI Technical Summary

Benefits of technology

[0012] Apparatus and methods are disclosed for forming DPP or LPP plasma generated EUV light source optical elements, e.g., reflectors comprising MLM stacks employing various binary layer materials and capping layer(s) including si

Problems solved by technology

In the process of the creation of the plasma for the emission of EUV light several harsh results of the plasma creation are released into the environment in the EUV light source generation chamber around the plasma that are potentially very damaging to materials comprising, e.g., the collector / director optical element, e.g., heat, high energy ions and scattered debris from the plasma formation, e.g., atoms or clumps of source material not ionized in the plasma formation process.

The heat, high energy ions and / or source material may be damaging to the optical elements in a number of ways, including simply heating them, penetrating into them and, e.g., damaging structural integrity and / or optical properties, e.g., the mechanics of MLM operation to reflect light at such short wavelengths, corroding or eroding them and / or diffusing into them.

In addition, the nature of debris management for the EUV light source chamber may result in increasing the harshness of the environment in which the MLM stack and its protective overcoating (capping) layer(s) need to operate and protect the underlying binary multilayer stack.

However applicants are not aware of use of yttrium for collector / director or other optics in a plasma generated EUV light source for protection of the optics, e.g., from a reactive source material, e.g., lithium.

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